a1. Under parts uniform gray.
b1. Lores and space in front of eyes deep black.
c1. Tail less than 140 mm.
d1. Feathers covering the nostrils deep black like the lores.
e1. Feathers of the rump gray, fringed with whitish; tail,
120 mm. ... striatus (p. 482)
e2. Feathers of the rump uniform gray; tail, 122 to 124
mm. ... mindorensis (p. 483)
d2. Feathers covering the nostrils gray like the crown; tail,
132 mm. ... cebuensis (p. 484)
c2. Tail more than 140 mm.; feathers covering the nostrils deep
black like the lores and the space in front of eyes; tail, 144
mm. ... guillemardi (p. 481)
b2. Lores and space in front of eyes pale gray like the crown;
general color pale gray. ... difficilis (p. 480)
a2. Throat and breast gray; belly and rest of under parts barred with
black and white.
b1. Lores and space in front of eye deep black; under tail-coverts
white, barred with black, the black bars extending right across
the feathers and being about two-thirds of the width of the white
interspaces. ... panayensis (p. 483)
b2. Lores and space in front of eye gray like the crown; under
tail-coverts uniform white; or white with rather narrow wide-set
black bars, which are generally confined to the middle of the
feathers. ... kochi (p. 482)